Study whether equivalent levels of circulating estradiol obtained by oral and by transdermal administration promote the same degree of GH stimulation. Subjects will be studied on three occasions: pretreament, after 14 days of treatment with oral estradiol, and after 14 days of transdermal estradiol treatment. Study completed and paper published. At relatively high doses the effects of transdermal E2 parallel those of oral E2 exactly, significantly elevating GH and SHBG concentrations, while decreasing circulating IGF-I levels. Our results suggest that, at least in the higher dose ranges, absolute E2 concentrations may be a more important determinant of endogenous GH production than route of administration. In this study transdermal E2, like oral E2, appears to function by decreasing circulating IGF-1, reducing negative feedback at the pituitary/hypothalamus and leading to increased GH production. A revision of this protocol (MOT090) will examine the effects of lower estradiol doses by both routes in the same population.